Centrifugal circuit-changing device for electric motors.



E. S. PILLSBURY.

CENTRIFUGAL CIRCUIT CHANGING DEVICE FOR ELECTRIC MOTORS.

APPLICATION FILED FEB. 23. 1915.

Patented Oct. 19, 1915.

2 SHEETS-SHEET l.

l E, s. PILLSBURY. CENTRIFUGAL CIRCUIT CHANGING DEVICE FOR ELECTRIC MOTORS.

APPLICATION FILED FEB. 23. 1915- 1,157,179. v Patented oct. 19, 1915.

2 SHEETS-SHEET 2.

viewed Afrom the right.

UNITED STATES PATENT oEEIoE.

EDWIN S.- ;PILLSBURY, OE ST. LOUIS, MISSOURI, ASSIGNOR TO CENTURIr ELECTRIQ COMPANY, or ST. LOUIS, MISSOURI, A CORPORATION or MISSOURI.

CENTRIEUGAI. CIRCUIT-CHANGING DEVICE FOR ELECTRIC MOTORS.

To all vwhom it may concern:

Be it known that I, EDWIN S. PILLSBURY, a citizen of the United States, residing in the city of St. Louis and State of Missouri,

have invented certain new and useful 1mprovements in Centrifugal Circuit-Changing Devices for Electric Motors, of which the following is a specification.

The principal Object of my invention is to provide`a new and improved device for utilizing centrifugal force to'.change the circuits of an electric motor at a critical increaseof speed.

Another object of my invention is to provide la serviceable and effective stop to limit the outward movement of the centrifugal weights.

Another object is to provide pivotal connections from these weights to the other mechanism so that the lwhole body of each weight shall move approximately radially.

' Other objects are to build the centrifugal mechanism so it will' occupy little space along the motor shaft and so that it can be conveniently assembled.v

All these objects and others will be made apparent in the following specification in which 1 describe one specic embodiment of my invention. 1t will be understood the invention is deiined in the appended claims.

Referringto the accompanying drawings; Figure 1 is a longitudinal section of a motor embodying my invention. Fig. 2 is a detail view looking in the direction of the arrow2 in Fig. 7. Fig.V 3 is a detail section on the line 3 of Fig. 6. Fig. 4 is a section Ithe same as for the corresponding part of Fig. 1 but with the shaft removed.-- Fig. 5 is an elevation rof the parts of Fig. 4 as Figs. 6 and 7 correspond respectively with Figs. 4 and 5 but showing the centrifugal weights displaced.

As shown in the drawings, the motor comprises the stator laminations 15 and the rotor laminations 16 fixed on the shaft 17. The commutator segments 18 are arranged radially so that the commutator surface is a plane transverse to the shaft 17. The brushes 19 normally press against the commutator but may be released by pushing to the left, as viewed in Fig. 1, on the members 20 carried by the parallel motion links 21. The sleeve 22 around the Specification of Letters Patent.

shaft 17 car- Patented oct. 19, 1915.

Application led February 23, 1915. Serial No. 9,986.

ries a circumferential series of short circuiting members 23, and centrifugal force causes them to press against the ring 24. When the sleeve 22 is pushed to the left, as viewed in Fig. 1, the members 23 connect the inner ends 25 of the commutator segments 18 to the ring 24, thus short circuiting the rotor coils. The sleeve 22 is fixed at its endI on the ring 28 and a Spring 26 acting between the ring 28 and abutment `27 on shaft 17, keeps the members 22 normally in the position shown in Fig. 1.

r1`he ring 28 carries two pins 29 withl sockets 30 which receive the ends of the rods 31 extending through slots 60 in the rotor 16. The shaft 17 has xed thereon a shoulder 32 against which rests a flange 33 forming an abutment at one end of the rotor laminations 16. At the other end is an annular cup with its base 35 against the laminations 16. The outer wall 34 of this cup is a cylin. rical shell and the inner wall 37 its around the shaft 17 and has its edge 39 crimped in the groove 38 around said shaft. Holes 36 are provided through the base 35 to acccominodatethe rods 31.

Within the shell 34 is a channel collar 40. From its outer flange on opposite sides there project two spring tongues 41 with outturned ends 42 that enter holes 43 in shell 34 and thus keep the collar 40 in place in shell 34. The lugs 44 may be engaged to remove he spring tongues 41, when the parts are disposed as in Fig. 7, and it is desired te remove collar 46.

From the inner flanges of the collar 46,

on opposite sides, there project two lugs 45 to which are connected the ends 47 of the bell-crank yokes 46 by means of the pivot pins 48. Each yoke 46 has a socket 49 at its middle point engaging the ball 50 on the end of the corresponding rod 31. Oneach .side each yoke 46 carries an arm 51 withits end attached by the pivotpin to one Side of the half shell 52. There are two\of these half shells 52, and each of them carries tongues 57 which project through correr sponding holes in v.a segment 56 and have their ends headed over so as to secure the parts 52 and 56 rigidly together. A halfshell 52 and its connected segment 56 constitute a centrifugal weight andv there are two such weights. Each half-shell 52 is notched at 53 toaccommodate the ball and socket joint 4.9-50 (see Fig. 4), and likewise notched at 54 to accommodate one end of arm 51 of -yoke or bell-crank 46.

The segments56 have the shape shown in Figs. 5 and 7. Each segment is cut away at one side at 58 and the Vother segment is extended at 59 to enter this cut-away place, as in Fig. 5. The object of this is to bring the center of mass of each centrifugal weight 52-56 closer to shaft 17; or otherwise expressed, to carry part of each weight 5,2-56, namely the part 59, past the axis of the shaft 17 so that its centrifugal force will act oppositely to the major portion of the weight 52-56 when in the position of Fig.

5, but therewith when in the position of Fig. 7. Thus when the weights 52-56 fly out by centrifugal force, they become increasingl-y effective to overcome the resistanceof the spring 26.

vWhen the motor is at rest the parts have the positions shown in Figs. l, 4 and 5.

When a single phase alternating current is applied the motor starts as a commutator motor. After a certain speed has been attained, the centrifugal Weights 52-56 fly out until the half-shells 52 strike the inside face of the shell 34, which acts as a stop. By this movement the bell-crank yokes 46 are carried from the position of Fig. 4 to that of Fig. 6, and push on the rods 31, and thereby shift the sleeve 22 and the short-cir- @uiting members 23 so as to connect the commutator segments 18 to the ring 24 and thus short circuit the rotor coils. At the same time the end of the sleeve 22 .pushes the members 20 and releases the brushes 19. Thereafter the motor runs as an induction motor. At slowing down and stopping the reverse operations occur as will be obvious.

The weights 52-56 move in a radial plane and substantially in a radial direction and 4each weight has no stationary pivot but its pivot and its Whole mass move all alike and with utmost effect, whereas if each weight had some part on a pivot fixed on the shaft 17, the part adjacentto such pivot would be ineffective. The centrifugal device is easy to manufacture, being made of sheetmetal punchings throughout, and it is easy to assemble, for the collar 40, yokes 46, rods 31 and weights 52-56 can be4 assembled, then the rods 31 thrust through the holes 36 into the sockets 30, the collar 40 slipping within the shell 34 and the ends 42 of the tongues 41 snapping into the holes 43 in the shell 34. Thus the Whole governor .mechanism can be assembled as a unit and i11- stantly applied to or detached from the rotor. The arran ement of the parts,l and particularly the at segments 56, cause the centrifugal mechanism Ato occupy very little longitudinal space on the shaft 17. The

stops 34 to engage the half-shells 52 'vef4 large wearing surface and strength an rigidity. There are no pivotal joints subjected to twisting strains. By actual trial in the testing room I have caused a motor constructed in accordance with this specification to make over one hundred thousand starts and thereafter it showed no appreciable wear on the parts of the centrifugal mechanism.

I claim:

1. In combination, a stator, a shaft journaled therein, a 'rotor on said shaft, a circuit-changing member carried by said shaft and adapted to slide longitudinally thereon, levers pivoted on the shaft and connected to said circuit-changing member, and centrifugal weights p'ivotally connected to said levers.

2. In combination, a stator, a shaft jou'rnaled therein, a rotor on said shaft, a circuit-changing member carried by said shaft and adapted to slide longitudinally thereon, a pair of opposite bell-cranks fulcrumed on said shaft with a common plane of movement containing the axis of the shaft, a pair of weights pivotallv attached to corresponding ends of respective bell-cranks, and rods connecting the remaining ends of said bellcranks to said circuit-changing member.

3. In combination, a stator, a shaftjournaled therein, a rotor on said shaft, a circuit-changing member carried by said shaft and adapted to slide longitudinally thereon, a pair of bell-cranks fulcrumed on said shaft with a common fulcrum axis at a right angle With the axis of the shaft and inthe same plane therewith, a pair of Weights pivotally attached to corresponding ends of the respective bell-cranks, and rods connecting the remaining ends of said bell-cranks to said circuit-changing member.

4. In combination, a stator, a shaft jou'rnaled therein, a rotor on said shaft, a circuit-changing member carried by said shaft and adapted to slide longitudinally thereon, a pair of bell-crank yokes on opposite sides of the shaft and pivoted at theirends on' pins fixed relatively to the shaft, the axis of these pivots for each bell-crank intersecting the shaft at a right angle to its axis, a pair of Weights pivotally attached to corresponding ends of the respective bell-cranks, and rods connectingv the remaining ends of said bellcranks` to said circuit changing member.

5. In combination, a stator, a shaft journaled therein, a rotor on said shaft, a circuit-changing member carried by said shaft 1 and adapted to slide ,longitudinally thereon,

a cylindrical shell fixed on said shaft at one end .of the rotor, mechanism'comprising centrifugal Weights ladapted to fasten in said shell and an operative connection from said mechanism to said circuit changing member.

6. In combination, a stator, a shaft jour- Analed therein, a rotor on said shaft, a circuit trifugall Weights adapted to fasten in saidV shell and an operative connection Lfrom said mechanism to said circuit changing member,

said shell being adapted to act as a stop for said Weights.

7. In combination, a stator, a shaft jour` naled therein, a rotor on said shaft, a circuit changing member carried by said shaft and adapted to slide longitudinally thereon, a cylindrical shelll Xed on said shaft at one end of the rotor, a collar adapted to fit in said shell, means to fasten said collardetachably therein, mechanisml comprising centrifugal Weights carried by said collar, and an operative connection from said mechanism to said circuitl changing member. v

8. In combination, a stator, a shaft journaled therein, a rotor on said shaft,.a circuit changing-member carried by said shaft and adapted to slide longitudinally thereon, a cylindrical shell fixed on said shaft at'one end of the rotor, a collar to fit in said shell, said shell having holes therethrough,l spring tongues carried by said collar adapted to snap in saidL holes, mechanism comprising centrifugal Weights carried by said collar and an operative connection from said mechanism to saidcircuit changing member.

9. In combination, a stator, a shaft journaled therein, a rotor on said shaft, a circuit changing member carried bv Said shaft and adapted to-slide longitudinally thereon," a-

cylindrical shell xed on said shaft at one end of the rotor, mechanism comprising centrifugal Weights adapted to t Within said shell, each centrifugal Weight consisting of a half-shell Within said lcylindrical shell and l a segment attached thereto extending across the end edge of the cylindrical shell, and an operative connection'from said mechanism to said circuit changing member.

10. In combination, a stator, a shaft journaled therein, a rotor on said shaft, a circuit changing. member carried by said shaft and adapted to slide longitudinally thereon, said shaft having a groove yaround it, an annular cup around said shaft with its base against one end of the rotor and its inner flange enga ing said groove, mechanism comprising centrifugal Weights adapted to fasten 'in said cup, and an operative connection from said mechanism to said circuit changing member, said shell being adapted to act as a stop for said Weights. vIn testimony whereof, I have subscribed my name.

EDWIN S. PILLSBURY Witnesses:

GEO. B. RICHARDS, J. M. CHANDLEE.` l 

